john brennan, the architect of the obama administration's drone program, strongly defended their use, saying strikes only take place to prevent terror threats, not as punishment for them. >> i think there is a misimpression on the part of some american people who believe that we take strikes to punish terrorists for past transgressions. nothing could be further from the truth. we only take such actions as a last resort to save lives when there's no other alternative to taking an action that's going to mitigate that threat. >> democratic senator ron wyden who has demanded more insight into the administration's legal justification for drone strikes against americans pressed brennan on the issue. >> do you believe that the president should provide an individual american with the opportunity to surrender before killing them? >> any american who joins al qaeda will know full well that they have joined an organization that is at war with the united states and has killed thousands upon thousands of individuals, many, many of them who were americans. so i think any american who did that shoul